rU8 



NEW YORK STATE MUSEUM 



petition in the market. In the best of slate quarries the propor- 

 tion of waste rook, that must be removed, to the marketable stock 

 is enormous. This is a constant expense, though the waste could 

 find a limited market for use on the local roads, which would not 

 only be a source of revenue to the quarrymen, but would also 

 cheapen transportation for them. Some of the quarries, particu- 

 larly in the Hatch hill group, where they are located in a depres- 

 sion, are necessarily open pits which require constant pumping. 

 But many others are located on side hills, where a cut or a tunnel 

 could be cheaply run in from below which would not only drain 

 the quarry but would provide a way for the removal of the slate 

 and the waste by gravity instead of by the slow and expensive 

 method of hoisting now in use. The initial cost of such an outlet 

 would be something of a burden, but this would soon be repaid 

 in an increased output and cheapened quarrying. 



The age of the slate deposits is carefully discussed by Prof. 

 T. Nelson Dale in the 19th report of the United States geological 

 survey, where he points out that the red slates are a part of the 

 Hudson river group, and the others are of Cambrian age. 



Sea green slate is typically a Vermont product. It belongs to 

 the Georgia group, the lowest formation of the Cambrian system, 

 and is quarried at many points, particularly between West Paw- 

 let and Poultney. Plate 37 is a distant view of the group of quar- 

 ries at the former town. It is stated that the sea green slate is 

 confined to Vermont, as closely as the red is confined to Nei? 

 York, though south of Granville they outcrop within half a miie 

 of each other. 



The slate formation can be traced southward from Washington 

 county, through Rensselaer, Columbia and Dutchess counties, and 

 is also found in Orange county. Red slate of Hudson river age 

 is exposed in a cut of the New York central railroad near Fish- 

 kill. William W. Mather, in Geology of the first geological distfidi 

 of Neic Torl\ p. 420, says, U A range of roofing slate extends from 

 New Lebanon through Canaan, Austerlitz, Hillsdale, Copake, 

 Ancram and Pulvers corners in Northeast. It is believed to be 

 the same as that in which the Hoosick quarries are.located. Quar- 



